


guilty or not, you pay the price

by hyliank8



Series: Wartime Sanster AU Collection [2]
Category: Undertale (Video Game)
Genre: Angst, Blood and Injury, Guilt, Heavy Angst, Helplessness, Human-Monster War (Undertale), Hurt No Comfort, M/M, Magic Blood, Painful Death, Powerlessness, Sadism, Slow Death, Torture, W. D. Gaster Is Not Related to Papyrus and Sans, Wartime Sanster AU, more angsty high fic from k8, soul torture, this is a tag now lolol
Language: English
Status: Completed
Published: 2021-02-06
Updated: 2021-02-06
Packaged: 2021-03-18 05:13:20
Rating: Mature
Warnings: Graphic Depictions Of Violence, Major Character Death, Rape/Non-Con
Chapters: 1
Words: 744
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/29238123
Author URL: https://archiveofourown.org/users/hyliank8/pseuds/hyliank8
Summary: Gaster and Sans are held captive by the Humans.Gaster fails to protect his best friend.(Wartime Sanster AU)(Русский перевод доступен в заметках автора. || Russian translation is available in the author's notes.)
Relationships: (latter two relationships are mainly just implied), Grillby & Sans (Undertale), Papyrus & Sans (Undertale), W. D. Gaster/Sans
Series: Wartime Sanster AU Collection [2]
Series URL: https://archiveofourown.org/series/2146950
Comments: 20
Kudos: 19





	guilty or not, you pay the price

**Author's Note:**

> FINALLY MORE WARTIME SANSTER 😭 lol i hav never used this many archive warnings on a single fic
> 
> this is one of those high things again so this is not proofread and i ammmm not sorry. it's almost 5am i should probably sleep bc i gotta get up in lie 5 hours loL
> 
> OH YEAH AND this also goes along with [this thing i posted on twitter](https://twitter.com/K8Maybe/status/1357802477689729025/photo/1) yesterday or today i can't remember 
> 
> **edit: one of my friends wrote a follow-up fic to this and it's amazing, i have it linked at the end of this fic--pls look out for it 😭👏**
> 
> also, [here's a translation into Русский/Russian!](https://ficbook.net/readfic/10406925) Thank you to [Darkened Soul](https://ficbook.net/authors/4341598) for translating :))
> 
> anyways pls enjoy pain

If Monsterkind wins the war it won’t matter. If the rest of Monsterkind is killed it still won’t matter. Gaster’s reason to live died slowly, agonizingly before his eyes. 

_“wings,” it hardly sounds like Sans’ voice, it’s so tortured. “i’m s-sorry... h-help m-me, please, it h-hurts—!”_

_He never begs. He never asks for Gaster’s help for anything._

_He must have been in agony._

_The humans laugh at his plead._

The scene before him is blurry—his eyes are unfocused, his gaze distant—but even though he can’t see it he’s acutely aware of the pile of dust lying in front of him.

“Whats the matter, monster?” one of the humans gloats. “Nothing clever to say now that your mate’s dead?”

Gaster barely hears him. Did he talk back to the humans before? He can’t remember. It’s all in another life now; it doesn’t matter.

He can’t stop hearing Sans’ screams ringing in his head.

“You really were only ever good for our entertainment, weren’t you?”

_“Shh... good little monster,” the human groans as they keep him trapped against the floor, rocking into him over and over again. “You like it when I use you like this, don’t you?”_

_Gaster ignores them, trying to block it all out. He just wants it to end._

_But he can’t hold back his scream when they sink their teeth into his flesh for the first time._

_When they pull back, his blood drips from their mouth. “You’re mine now, monster,” they growl._

_That isn’t the last mark they give him._

“How did it feel to watch him turn to dust as he begged for you to save him?”

_“stop!” Sans shrieks. “stop! please! i’ll do anything!” Gaster has never heard him cry for mercy before. A merciless hand squeezes into his soul, the shuddering organ constricting in the unforgiving grip and beginning to break apart, oozing between the spaces between the human’s fingers._

_It’s torture. Gaster knows it must be torture; it’s the most intimate part of Sans’ existence and they’re strangling it, forcing it apart in their fist._

_Sans_ _screams_ _._

_“WINGS!” His voice tears from his throat as his agony rips his natural font into uppercase. “PLEASE!”_

“How does it feel knowing that you could have stopped it if you weren’t so weak?”

_Gaster strains against the magic-suppressing bindings, the gag preventing him even from crying out. He needs to break out of this hold, he needs to get to Sans, he needs to get them out of here, he needs...._

“But you’re worthless, aren’t you? Couldn’t even save your own mate.”

_Gaster wants to hold him. He wants to tell him it’s going to be okay. He wants to whisper soothing words, watch his lover’s brow uncrease as his torment melts away._

_But he can’t. As he lay on his side, Sans’ eyelights are distant, terrified pinpricks. They tremble, shining with his agony._

_Sans can’t talk anymore, Gaster knows. The pain is too much. Shuddering breaths leave him. It’s clear they’re his last few._

_Gaster still can’t speak past the gag, helpless to do anything as Sans’ body twitches, involuntarily convulsing from the abuse to his soul. He coughs and a stream of blood and raw magic spills forth from between his teeth, spattering red and blue onto the floor below._

_Blood and magic steadily begins to pool on the floor as the coughing continues. As the gut-wrenching hacking gradually dissolves into labored breaths, his body’s twitches come less frequently. Red and blue continues to dribble from his parted, slack maw, spilling out as though every shuddering breath he takes is pushing out more of it._

_Even his breathing is working towards killing him._

_Sans’s hazy eyelights drift over in Gaster’s direction, and he meets Gaster’s gaze. Gaster can see it in his eyes; he’s in so, so much pain. Gaster would do anything to make it stop._

_“...w...ings...” Gaster barely manages to hear the croaked words. “i’m s...orry...”_

_It’s his last breath._

_Sans’ expression is still poisoned by agony as his body turns to dust._

Gaster remains silent. They’re right. He vowed to protect Sans from the moment the war began. He promised himself he’d never let anyone harm his best friend.

Some monsters looked forward to the glory of fighting in the war, but Sans never wanted to hurt anybody. He only ever wanted those he loved to be safe. His little brother. Grillby. Gaster.

_He was innocent... and I failed him._

**Author's Note:**

> eeheeeee i hav nothing 2 say here. i am probably not going to remember in the morning that i posted this so, @ future me: enjjoyyyyy :)))
> 
> oh wait also yeah i headcanon tht it is actually physically Painful 4 lowercase font monsters 2 speak in uppercase,,,, i think this was noel's idea originally but i lov it so here it is in a fic whee
> 
> here's [tumblr](https://hyliantimelordin221b.tumblr.com/) n [twitter](https://twitter.com/K8Maybe)
> 
> **edit: my Wonderful friend QuintessenceA[wrote a follow-up to this!!!](https://archiveofourown.org/works/29263104) it is So good and i am Dying!!! it's even longer than this one and it's so heartbreaking, pls check it out!!! 😭👏💖 **
> 
> if u comment i lov u sm 🥺

**Works inspired by this one:**

  * [Why You Shouldn't Play With Fire](https://archiveofourown.org/works/29263104) by [QuintessenceA](https://archiveofourown.org/users/QuintessenceA/pseuds/QuintessenceA)




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